Downhole Turbine Communication

ABSTRACT

In one aspect of the present invention a downhole drill string assembly includes a bore there through to receive a flow of drilling fluid, a signal generator that produces a signal in the drilling fluid by rotating within the flow, a processing unit disposed within the assembly, and a flow guide that directs drilling fluid to the signal generator. The flow guide is in communication with the processing unit so that in response to commands received from the processing unit, the signal generator produces a signal in the drilling fluid by the flow guide changing its position.

BACKGROUND OF THE INVENTION

Measurement while drilling is a system that can be used to communicate between a downhole tool and surface equipment in a downhole drill string. Such system may include mud pulse telemetry, which sends signals through the fluid in the drill string's bore. The prior art discloses mud pulse telemetry systems.

One such mud pulse telemetry system is disclosed in U.S. Pat. No. 5,215,152 to Duckworth, which is herein incorporated by reference for all that it contains. Duckworth discloses a rotating pulse valve for use in a mud pulse telemetry system is presented. In accordance with the invention, a valve is diametrically mounted in a channel of a segment of a drill string wherein drilling fluids flows. The valve comprises blades which are configured so as to be impelled (i.e., rotated) by the flow of the drilling fluid. An escapement mechanism is employed to restrain the valve in selected positions thereby at least partially obstructing the flow of the drilling fluid which results in generating positive pressure pulses or waves in the drilling fluid in response to downhole conditions.

Another such mud pulse telemetry system is disclosed in U.S. Pat. No. 6,097,310 to Harrell, which is herein incorporated by reference for all that it contains. Harrell discloses a mud pulse telemetry system uses a downhole pulser to produce sequences of positing and/or negative pulses according to a selected pattern. Positive pulses, a negative pulses, and combinations thereof may be produced. A flow rate sensor at the surface measures changes in the flow rate at the top of the wellbore instead of or in addition to changed in the pressure. The flow rate changes are detectable even though the pressure pulses themselves may have a poor signal to noise ratio. This enables the invention to function effectively in underbalanced drilling wherein the use of light muds with a high gas content is required. One embodiment of the invention uses a conventional downhole pulser with the main valve closed and the pilot valve operating in a direct pulse mode.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention a downhole drill string assembly includes a bore there through to receive a flow of drilling fluid, a signal generator that produces a signal in the drilling fluid by rotating within the flow, a processing unit disposed within the assembly, and a flow guide that directs drilling fluid to the signal generator. The flow guide is in communication with the processing unit so that in response to commands received from the processing unit, the signal generator produces a signal in the drilling fluid by the flow guide changing its position.

The flow guide may be located up stream and proximal to the signal generator. It may be comprised of a plurality of flow blades wherein the plurality of flow blades is mechanically connected to a rotatable plate. The flow guide may alter the flow of the drilling fluid such that the flow guide itself produces a signal. If the signal is generated from the flow guide itself or from the signal generator, the flow guide determines the frequency and the bandwidth of the signal. The signal produced may be a sound wave or a pressure wave.

The signal generator may include a turbine which would be exposed to the drilling fluid. A fluid guide, in communication with the processing unit, may alter the angle of attack of the drilling fluid across the turbine or the fluid may be altered by the flow guide so that the turbine produces a signal.

In the presence of a turbine, the signal generator may include a rotary valve. The rotary valve is located down stream and in mechanical communication with the turbine, and exposed to the drilling fluid. The rotary valve may comprise a stator plate and a rotor plate. Both the stator plate and the rotor may comprise a plurality of ports. The rotor plate may rotate around a center axis according to the rotation of the turbine. As the rotor plate rotates, the port on the rotor plate and the ports on the stator plate align or misalign, thus, altering the flow of the drilling fluid producing a signal.

The downhole drill string assembly may also include a signal sensor. The signal sensor would be exposed to the drilling fluid and in communication with the processing unit. In response to a signal received by the signal sensor, the signal generator may repeat the signal.

A plurality of signal generators may be disposed within the drill string.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an embodiment of a drill string.

FIG. 2 is a partial cross-sectional view of an embodiment of a downhole tool.

FIG. 3 is an exploded view of an embodiment of a rotary valve.

FIG. 4 is a perspective view of an embodiment of a downhole tool.

FIG. 5 is a perspective view of an embodiment of a downhole tool.

FIG. 6 is a partial cross-sectional view of an embodiment of a downhole tool.

FIG. 7 is a perspective view of an embodiment of the flow guide.

FIG. 8 is a partial cross-sectional view of an embodiment of a downhole tool.

FIG. 9 a is a partial cross-sectional view of an embodiment of a downhole tool.

FIG. 9 b is a partial cross-sectional view of an embodiment of a downhole tool.

FIG. 10 is a partial cross-sectional view of an embodiment of a downhole tool.

FIG. 11 is a perspective view of an embodiment of a downhole tool.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

FIG. 1 discloses an embodiment of a downhole tool string 100. The tool string 100 may be suspended by a derrick 108 within an earthen formation 105. The tool string 100 may compose a drill bit 104 and one or more downhole components 103. The downhole tool string 100 may be in communication with surface equipment 106.

FIG. 2 discloses an embodiment of a downhole tool 103 with a first end 202 and a second end 203. First end 202 may connect to a portion of drill string that extends to the surface of a borehole, and the second end 203 may connect to a bottom hole assembly or drill bit or other drill string segments. Downhole tool 103 comprises a flow guide 204 and a signal generator that may include a turbine 205 and a rotary valve 206. The rotary valve 206 may be may mechanically connected to the turbine 205. The turbine 205 or the rotary valve 206 of the signal generator may produce a signal 207 in the drilling fluid.

FIG. 3 discloses an embodiment of the rotary valve 206 that is exposed to the drilling fluid. The rotary valve 206 may comprise a stator plate 301 and a rotor plate 302. Both the stator plate 301 and the rotor plate 302 may contain a plurality of ports 303. The rotor plate 302 may rotate relative to the turbine and about its central axis 304. The stator plate 301 may stay stationary. As the rotor plate 302 rotates, the plurality of ports 303 align and misalign altering the flow of the drilling fluid. As the drilling fluid is altered, a signal is generated at a first frequency.

Changing the rotational speed of the turbine will change the frequency that the ports align and misalign, thereby, changing the signal's frequency. In some embodiments, the signal generated by the signal generator may be a sound wave, a pressure wave or combinations thereof.

FIG. 4 discloses an embodiment of a downhole tool containing the flow guide 204, and a signal generator. In this embodiment, the signal generator comprises the turbine 205 and the rotary valve 206. The flow guide 204 may comprise a plurality of flow blades 401. The flow blades 401 may be used to direct the flow of the drilling fluid across the turbine blades. In this embodiment, the flow blades 401 are arranged parallel to the drilling fluid, so the flow blade 401 are directing the drilling fluid in a direction consistent with the fluid's flow.

FIG. 5 discloses an embodiment with the flow blades 401 angled. The flow guide 204 now directs the fluid to engage the turbine's blade at a different angle, which, in the embodiment of FIG. 5, is more aggressive than show in FIG. 4. This will cause the turbine to rotate at a faster rate, and thus, change the generated signal's frequency.

Thus, the signal's frequency is dependent on the flow guide's position. The position of the flow blade may cause a more or less aggressive attack angle. In some embodiments, the flow blades 401 may even rotate such that the fluid flow is blocked off. By changing the generated signal's frequency, encoded signals may be transmitted through the fluid in the drill string's bore. One advantage of the present invention, the is quick response time to change the turbine's rotation, and thereby, change the signal generators frequency change.

Communicating quickly in a well bore is essential, especially in emergency situations. Further, when multiple sensors and downhole instrumentation are trying to send signals to the surface through the signal generator, quick signals are desirable. The prevent invention's response time to changing the signal generator's frequency enables more encode messages to be sent to the surface in a shorter amount of time.

FIG. 6 discloses an embodiment of the signal produced by the signal generator. As the flow guide changes the flow of the drilling fluid, the frequency of the signal 604 changes. FIG. 6 discloses an embodiment of modulated signal 604.

FIG. 7 discloses a flow guide 701 comprising a rotatable plate 702 and a plurality of flow blades 703. The flow blades 703 may attach to the guide through a pivot point 704. The rotatable plate 702 may contain slots 705 disposed around its circumference. The slots 705 may be adapted to receive tabs 706 disposed on the flow blades 703. The tabs follow in the slots when the rotatable plate turns causing the flow blades 703 to rotate on their pivot point 704.

FIG. 8 discloses a downhole tool string comprising a plurality of signal generators. A plurality of signal generators may be disposed along the bore to facilitate a signal traveling up the bore. A plurality of signal generators may be useful in situations where the signal doesn't have enough strength to travel to the top of the drill string on its own. A signal generator 801 is associated with a signal sensor 802 and is contained within the bore. The signal sensor 802 may receive a first signal 803 from traveling up the bore. As the signal sensor 802 receives a first signal 803, the signal generator 801 may repeat the first signal 803 by producing a second signal 804 identical to the first signal. The sensor may be in electrical communication with a flow guide of the second signal generator to repeat the signal. In other embodiments, the second signal generator comprises a piezoelectric or magnetostrictive material that generates the desired encoded signal.

FIG. 9 a discloses a downhole tool string comprising a plurality of signal generators 902. The signal produced by a signal generator can be a pressure wave, sound wave, or other type of signal within the scope of the invention. In this embodiment, the arrows 901 represent the pressure that is associated with the system when a pressure wave is not produced from a signal generator.

FIG. 9 b discloses the same downhole tool string as in FIG. 9 a but the signal generators 902 are producing a pressure wave which is represented by the arrows 903. The pressure wave generated from the signal generators 902 go up the bore and thus oppose the pressure that is normally felt down the bore. In this embodiment, a plurality of signal generators may be utilized to sense the pressure build-up and re-transmit the signal upward.

FIG. 10 is another embodiment of a signal generator. This embodiment shows a signal generator without a rotary valve. The flow guide 1003 alters the flow across the turbine 1001. In this embodiment, a frequency emitted by the rotation of the turbine 1001 itself is used as the transmission signal 1002.

FIG. 11 discloses another embodiment of a signal generator where the amount of flow over the turbine controls the turbine's rotation speed, and therefore, the frequency emitted by the signal generator. Here, a plurality of plates is used to restrict the flow. The flow guide 1101 may be comprised of a first plate 1102 comprising of a plurality of ports 1104 and a second plate 1103 comprising of a plurality of ports 1105. The first plate 1102 may be stationary and the second plate 1103 may rotate around a center axis. As the second plate 1103 rotates, the ports 1105 align and misalign with the ports 1104. As the ports 1105 and ports 1104 change relative to each other, the flow of the drilling fluid is altered and thus redirected across the turbine 1106. As the fluid flow is altered, a signal may be produced.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention. 

1. A downhole drill string assembly, comprising: a bore there through to receive a flow of drilling fluid; a signal generator that produces a signal in the drilling fluid when rotating within the flow; a processing unit disposed within the assembly; and a flow guide that directs drilling fluid to the signal generator; wherein the flow guide is in communication with the processing unit so that in response to commands received from the processing unit, the signal generator produces a signal in the drilling fluid by the flow guide changing its position.
 2. The assembly of claim 1, wherein flow guide is in communication with the processing unit so that in response to commands received from the processing unit the flow guide alters the flow of the drilling fluid such that a signal is produced.
 3. The assembly of claim 1, wherein the signal generator comprises a turbine disposed within the bore and exposed to the drilling fluid.
 4. The assembly of claim 3, wherein the flow guide is in communication with the processing unit so that in response to commands received from the processing unit, the flow guide alters an angle of attack of the drilling fluid across the turbine.
 5. The assembly of claim 3, wherein the flow guide is in communication with the processing unit so that in response to commands received from the processing unit, the flow guide alters the flow of the drilling fluid across the turbine such that the turbine produces a signal.
 6. The assembly of claim 3, wherein the signal generator comprises a rotary valve disposed within the bore, is located down stream from and in mechanical communication with the turbine, and exposed to the drilling fluid.
 7. The assembly of claim 5, wherein the rotary valve comprises a stator plate and a rotor plate with each comprising a plurality of ports.
 8. The assembly of claim 7, wherein as the rotor plate rotates around a center axis, the ports on the rotor plate and the ports on the stator plate align or misalign thus altering the flow of the drilling fluid such that a signal is produced.
 9. The assembly of claim 1, further comprising a signal sensor disposed within the bore and exposed to the drilling fluid and in communication with the processing unit.
 10. The assembly of claim 9, wherein in response to a signal received by the signal sensor, the signal generator repeats the signal.
 11. The assembly of claim 1, further comprising a plurality of signal generators located within the drill string.
 12. The assembly of claim 1, wherein the flow guide is up stream and proximal to the signal generator.
 13. The assembly of claim 1, wherein the flow guide determines the frequency of the signal.
 14. The assembly of claim 1, wherein the flow guide determines the bandwidth of the signal.
 15. The assembly of claim 1, wherein the signal is a sound wave.
 16. The assembly of claim 1, wherein the signal is a pressure wave.
 17. The assembly of claim 1, wherein the flow guide comprises a plurality of flow blades.
 18. The assembly of claim 17, wherein the plurality of flow blades is mechanically connected to a rotatable plate that moves the blades. 